of copper, rhodium, and gold formulate a one‐pot multistep pathway, which directly gives 2,5‐dihydropyrroles starting from terminal alkynes, sulfonyl azides, and propargylic alcohols. Initially, copper‐catalyzed 1,3‐dipolar cycloaddition of terminal alkynes with sulfonyl azides affords 1‐sulfonyl‐1,2,3‐triazoles, which then react with propargylic alcohols under the catalysis of rhodium. The resulting
A new procedure for the stereoselective synthesis of syn alpha-amino beta-oxy ketones is reported. It consists of two steps; in the first step, alpha-amino silyl enol ethers having a (Z) geometry are prepared from 1-alkynes via 1-sulfonyl-1,2,3-triazoles. In the second step, the silyl enol ethers undergo the TiCl4-mediated Mukaiyama aldolreaction with aldehydes to produce alpha-amino beta-oxy ketones
Synthesis of 2-Substituted 2-Amino Ketones by Rhodium-Catalyzed Reaction of<i>N</i>-Sulfonyl-1,2,3-triazoles with 2-Alkenols
作者:Tomoya Miura、Takamasa Tanaka、Qiang Zhao、Scott G. Stewart、Masahiro Murakami
DOI:10.1002/hlca.201600320
日期:2017.2
A study on a rhodium(II)‐catalyzed reaction of N‐sulfonyl‐1,2,3‐triazoles with 2‐alkenols is reported. The reaction is initiated by insertion of an α‐imino carbene into the O–H linkage of alcohol, forming a 2‐alkenoxy enamide intermediate. A thermal [3,3]‐sigmatropicrearrangement follows to yield 2‐substituted 2‐amino ketone in a stereoselective manner. The successful application of this methodology
N-Sulfonyl-1,2,3-triazoles react with water in the presence of a rhodium catalyst to produce alpha-amino ketones in high yield. An intermediary alpha-imino rhodium(II) carbenoid undergoes insertion into the O-H bond of water. This transformation formally achieves 1,2-aminohydroxylation of terminal alkynes in a regioselective fashion when combined with the copper(I)-catalyzed 1,3-dipolar cycloaddition with N-sulfonyl azides.
Site-Selective Introduction of an Enamido Group at the C(3)-Position of Indoles
An enamido group is introduced site-selectively at the C(3)-position of indoles by the rhodium(II)-catalyzed reaction with N-sulfonyl-1,2,3-triazoles. Formally, an alpha-imino rhodium carbene complex is inserted into the C(3)-H bond of an indole.